Subtract 30/20 from 12/21
1st number: 12/21, 2nd number: 1 10/20
12/21 - 30/20 is -13/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
12/21 = 12 × 20/21 × 20 = 240/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
30/20 = 30 × 21/20 × 21 = 630/420 - Subtract the two like fractions:
240/420 - 630/420 = 240 - 630/420 = -390/420 - After reducing the fraction, the answer is -13/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-30/20 12/21-60/20 12/42-30/20 12/21-30/40 36/21-30/20 12/21-90/20 12/63-30/20 12/21-30/60 60/21-30/20 84/21-30/20